Rod Bearing brand options? - OEM, ACL, VAC, BE, King Race

[BL92]

Brilliant, Cheers for the replies, I have M11 bolt, 01 engine, build number 27xx

Yevs build video is good, he just torqued up his M11 ARPs though, not stretched ?
The bimmer barn, i will following more his steps as they are as per bulletin

[bavarian3]

Brilliant, Cheers for the replies, I have M11 bolt, 01 engine, build number 27xx

Yevs build video is good, he just torqued up his M11 ARPs though, not stretched ?
The bimmer barn, i will following more his steps as they are as per bulletin

Not sure I would use yves videos as a good example for work like this. Use a stretch gauge. What is an extra $150 bucks to do the engine right? Also don't friggin lube the inner side of the bearing and cap.

[BL92]

Thanks Bavarian3, What about the ECS tuning guide?

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=http://bd8ba3c866c8cbc330ab-7b26c6f3e01bf511d4da3315c66902d6.r6.cf1.rackcdn.com/PDF_28814_BMW_S54_WPC_Treated_Rod_Bearing_Kit_Installation_-_ECS.pdf&ved=2ahUKEwiKmbTg0-qLAxWpplYBHZ0MLwQQFnoECBcQAQ&usg=AOvVaw0T2FL09Rhe-h0EHXoI48qp

[bavarian3]

Thanks Bavarian3, What about the ECS tuning guide?

https://www.google.com/url?sa=t&sour...he-h0EHXoI48qp

yes I used this, great documentation.

[x Spades x]

Quick questions for everyone...

Why would anyone do the bearings job with oem bearings when the issue is the oem bearings clearances being too tight? Isn't that just replace a problem with the same problem and guaranteeing that you'll have to do the job again in about 100k miles and be paranoid over the last 20k?

If someone get ACL extra clearance (for example), why wouldn't this be a one time bearing job for the life of the car? Again if clearances are the issue and you have extra clearance bearings, shouldn't this be all you need 500k miles?

[eacmen]

Quick questions for everyone...

Why would anyone do the bearings job with oem bearings when the issue is the oem bearings clearances being too tight? Isn't that just replace a problem with the same problem and guaranteeing that you'll have to do the job again in about 100k miles and be paranoid over the last 20k?

If someone get ACL extra clearance (for example), why wouldn't this be a one time bearing job for the life of the car? Again if clearances are the issue and you have extra clearance bearings, shouldn't this be all you need 500k miles?

Not sure we can agree that the root cause is tight bearing clearance. The root cause is commonly believed to be journal width is too small.

I don't think just running ACL bearings will allow you to not change bearings on an interval.

[JakeM346]

Sorry but this is all such…..half way information. The clearances of the bearings are not tooooooo tight. People always think if the bearings wears there’s just not enough oil in the gap so we need to make the gap bigger to expand the oil reservoir. This is not a completely wrong approach to a certain extent but can be easily overdone.
oil films are incredibly thin around 0,0005 mm this is 1/160 of a human hair. So when expanding the gap you actually increase the possibility of oil starvation due to higher side leakage rates.
There are ways to increase oil Film thickness by increasing eccentricity.
but honestly with the s54 it’s a general problem of the system. If you think about it logically p=mv so impulse/force on the bearing is mass times speed….the s54 piston keep their mass but the faster they rotate the more energy the rod bearings have to take…
meanwhile the oil supply need to keep up because with more compressions in a shorter time more oil gets squeezed out of the gap between bearing and journal which then need to be refilled by the oil pump supply in a shorter time more time. Oil pumps however need to be regulated to be energy efficient and to not produce to much pressure and therefore they are constructed to have an optimum operating window which is basically never at redline since street engines normally don’t get driven in this area that often.
also there are factory like crankshaft out of round, harmonics and the rods which at these speed start stretching. Actually all s54 bearings show quite nice signs of this happening by the wear on the meeting edges of the bearings.

also bmw engineers are wayyyyyy more intellegent and have access to incredibly nice simulation software….speaking here from experience
so if it would be as simple as increasing clearance bmw would have done it in 2003 when the recall happened.
instead they changed to bearings from bi to tri metal for higher fatigue strength and also the first oil pumps due to insufficient flow…

basically what I want to say I choose a bearing with a good fatigue strength especially in the overlay….some good eccentricity and best also replace the oil pump ….but definetly inspect it….
anything else is just…..a sales pitch of aftermarket rod bearing manufacturers or others (honestly take your pick)

personally from what I’ve seen all are good…
clevite are a factory supplier of bmw-see original bearings
king racing- have a clue about what they are talking about there head of R&D is actually really well know in the area of bearing design
Acl- haven’t looked at them this much but cheap and seem to work

and since the rod bearings are basically a maintenance item….why not cheap….

And also if you really wanna prolong s54 engine life especially rod bearings……yearly regular oil changes

[Obioban]

Quick questions for everyone...

Why would anyone do the bearings job with oem bearings when the issue is the oem bearings clearances being too tight? Isn't that just replace a problem with the same problem and guaranteeing that you'll have to do the job again in about 100k miles and be paranoid over the last 20k?

If someone get ACL extra clearance (for example), why wouldn't this be a one time bearing job for the life of the car? Again if clearances are the issue and you have extra clearance bearings, shouldn't this be all you need 500k miles?

The "bearing too tight" theory applies to the S85/S65. The S54 follows conventional bearing clearance methodology, unlike them.
(that said, I don't think the spec on the S65/S85 is wrong, either, but that's no the question at hand).

Going looser on the S54 would get you out of conventional and into "bearing too loose" territory, which is almost certainly going to get you a much shorter life span than stock.

Why replace them? Because bearings on high RPM engines wear out. BMW M cars, porsche GT cars, even high RPM hondas engines that get used hard-- engines that rev need bearing replacement.

[Cronenberged]

Thank you all for your answers

I have a FCP euro Rod bearing kit for sale if you’re still shopping.

[JakeM346]

The "bearing too tight" theory applies to the S85/S65. The S54 follows conventional bearing clearance methodology, unlike them.
(that said, I don't think the spec on the S65/S85 is wrong, either, but that's no the question at hand).

Going looser on the S54 would get you out of conventional and into "bearing too loose" territory, which is almost certainly going to get you a much shorter life span than stock.

Why replace them? Because bearings on high RPM engines wear out. BMW M cars, porsche GT cars, even high RPM hondas engines that get used hard-- engines that rev need bearing replacement.

Actually also not really true. S65 ist perfectly fine ….. have a read

https://marmotorsport.com/wp-content/uploads/MAHLE-Motorsport-High-Performance-Engine-Bearings-for-the-BMW-S65-S85-Iss.-2.pdf

what you said about s54 increase …. I said it before there you’re right

problem with most people especially s65 is simply the oil aging over time and use and also…. Partly the reduction of zddp in the oil

[Obioban]

Actually also not really true. S65 ist perfectly fine ….. have a read

https://marmotorsport.com/wp-content/uploads/MAHLE-Motorsport-High-Performance-Engine-Bearings-for-the-BMW-S65-S85-Iss.-2.pdf

what you said about s54 increase …. I said it before there you’re right

problem with most people especially s65 is simply the oil aging over time and use and also…. Partly the reduction of zddp in the oil

Yeah, as I said, I don’t believe the s65 bearings to be the cause is issues— just trying to separate the s54 and s65 conversations.

[Obioban]

Actually also not really true. S65 ist perfectly fine ….. have a read

https://marmotorsport.com/wp-content/uploads/MAHLE-Motorsport-High-Performance-Engine-Bearings-for-the-BMW-S65-S85-Iss.-2.pdf

what you said about s54 increase …. I said it before there you’re right

problem with most people especially s65 is simply the oil aging over time and use and also…. Partly the reduction of zddp in the oil

As I said, I don’t believe the s65 bearings to be the cause of its issues— just trying to separate the s54 and s65 conversations.

People claim the S65 wears bearings due to bearing clearance. Nobody thinks that of the S54.

[chris719]

Actually also not really true. S65 ist perfectly fine ….. have a read

https://marmotorsport.com/wp-content/uploads/MAHLE-Motorsport-High-Performance-Engine-Bearings-for-the-BMW-S65-S85-Iss.-2.pdf

what you said about s54 increase …. I said it before there you’re right

problem with most people especially s65 is simply the oil aging over time and use and also…. Partly the reduction of zddp in the oil

It has nothing to do with ZDDP. ZDDP only has an effect on mixed and boundary lubrication regimes, not hydrodynamic. Even if the hydrodynamic regime is exited and contact between the crank journal and bearing occurs, it is too severe for ZDDP to have any effect, you would need an EP additive as in gear oils. ZDDP also does not form protective phosphorus glass films much on non-ferrous metals like the bearing overlays. It’s by far the most effective on two ferrous metal surfaces.

S65 bearing issue root cause is complicated and probably involves oiling, tolerance stack, harmonics, and main bearing material harming the rod bearings. As we see now many S65 are eating main bearings.

[JakeM346]

It has nothing to do with ZDDP. ZDDP only has an effect on mixed and boundary lubrication regimes, not hydrodynamic. Even if the hydrodynamic regime is exited and contact between the crank journal and bearing occurs, it is too severe for ZDDP to have any effect, you would need an EP additive as in gear oils. ZDDP also does not form protective phosphorus glass films much on non-ferrous metals like the bearing overlays. It’s by far the most effective on two ferrous metal surfaces.

S65 bearing issue root cause is complicated and probably involves oiling, tolerance stack, harmonics, and main bearing material harming the rod bearings. As we see now many S65 are eating main bearings.

interesting. But also appears logical to me ….. so strike that comment.
s65 main bearing wear is normally in the first bearing with the chain. Which is normal for these duplex chains….seen the same in the s54 engine. Chain bearing wears more in direction of chain tension.

[digger]

Actually also not really true. S65 ist perfectly fine ….. have a read

https://marmotorsport.com/wp-content/uploads/MAHLE-Motorsport-High-Performance-Engine-Bearings-for-the-BMW-S65-S85-Iss.-2.pdf

what you said about s54 increase …. I said it before there you’re right

problem with most people especially s65 is simply the oil aging over time and use and also…. Partly the reduction of zddp in the oil

so Mahle made original bearings and now we have Mahle MS saying they were good......lol

IMO you would need your head read to use anything near 0.001" clearance on a Sxx engine which is what is at the lowend of permissible. IMO the range provided is too large

there is obviously alot more to bearing life than simply the clearance but BMW's clearance spec is a joke, obviously its a tough thing to mass produce and control the tolerance band but Mahle's own guidelines say for 0.00075 to 0.001 per inch of shaft +0.0005 for a high performance engine which is roughly 0.0020 to 0.0025 so we as individuals would be much better to follow this than the "BMW" spec which is based on what they can achieve on 10's of thousands of engines in a mass production environment.